SRC/dsterf.f(3)

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version 3.12.1 · 7 versions
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💅 SRC/dsterf.f(3) — Library Functions Manual 💅

okay so welcome to the page for SRC/dsterf.f(3) from the Library Functions Manual. It’s giving LAPACK subroutine energy, and the main character is DSTERF ✨.

🌸 NAME 🌸

SRC/dsterf.f — that’s literally the name, bestie.

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine dsterf (n, d, e, info)
    DSTERF

🦋 Function/Subroutine Documentation 🦋

subroutine dsterf (integer n, double precision, dimension( * ) d, double precision, dimension( * ) e, integer info)
    DSTERF

🎀 Purpose 🎀

DSTERF computes all eigenvalues of a symmetric tridiagonal matrix using the Pal-Walker-Kahan variant of the QL or QR algorithm. No cap, that’s the whole purpose.

🌈 Parameters 🌈

vibe check on the arguments, bestie:

  • N — INTEGER. The order of the matrix. Constraint: N >= 0. Respect the boundary.
  • D — DOUBLE PRECISION array, dimension (N). On entry, the n diagonal elements of the tridiagonal matrix. On exit, if INFO = 0, the eigenvalues in ascending order. So it comes in as diagonals and leaves as sorted eigenvalues when everything’s slay.
  • E — DOUBLE PRECISION array, dimension (N-1). On entry, the (n-1) subdiagonal elements of the tridiagonal matrix. On exit, E has been destroyed. Yep, gone. It ate and left no crumbs.
  • INFO — INTEGER. Exit-status tea:
    • = 0: successful exit.
    • < 0: if INFO = -i, the i-th argument had an illegal value.
    • > 0: the algorithm failed to find all of the eigenvalues in a total of 30*N iterations; if INFO = i, then i elements of E have not converged to zero.

👑 Author 👑

These are the academic icons behind it:

  • Univ. of Tennessee
  • Univ. of California Berkeley
  • Univ. of Colorado Denver
  • NAG Ltd.

Definition at line 85 of file dsterf.f.

👑 Author 👑

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And the footer sign-off, bestie: LAPACK, Version 3.12.0, page SRC/dsterf.f(3) 💖✨

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